Middle schoolers see themselves primarily through the lens of others—mostly their peers—in this phase. They look at and measure most things about who they are and what they have against that of the people they see around them.
As you talk about this comparison cycle, don’t belittle what they may be comparing. Truth be told, as adults we’re still struggling with so many of the same things!
Instead of simply pointing them away from comparison, do your best to emphasize the need to replace that habit with something different—something better. Point them toward things like celebration, inclusion, or acceptance. These are all things God offers to them, and they can begin to find those things in Him. It may not stop the comparison cycle, but it will plant seeds of what is true that they’ll remember and go back to as they grow and develop.